Mac window preview: how to see a window before you switch to it
You have six windows of the same app open and you want the one with the right document — but Cmd-Tab only shows app icons, and the Dock won't tell you what's inside each window either. What you want is a Mac window preview: a look at the actual contents of a window before you commit to switching to it. macOS gives you some of this natively, hides the rest, and leaves one gap that a handful of small apps exist to fill.
Here's every honest option, what each one previews, and how to pick.
Two jobs hide behind "window preview"
It's worth splitting the request, because the tools split along the same line:
- Peek without switching — hover or glance at an app's windows to see what's there, then decide. You're not necessarily switching; you're checking.
- Preview while you switch — as you flip between windows, see a thumbnail of each so you land on the right one first try. The preview is part of the switch.
macOS handles the second job better than the first. Let's take them in order.
What macOS previews for you natively
App Exposé — the current app's windows
Press Control-Down Arrow (or swipe down with three or four fingers, if that gesture is enabled in Trackpad settings) and macOS spreads out every open window of the active app as live previews — including windows on other Spaces. This is the fastest native "show me this app's windows" move, and most people have never mapped it. Click a preview to jump to it, or press Escape to back out.
Mission Control — every window at once
Control-Up Arrow (or F3) fans out all your windows on the current Space as previews, with your Spaces along the top. It's the wide-angle view: good for "where did that window go," less good for a quick same-app peek. Turn on Group windows by application in System Settings → Desktop & Dock and Mission Control clusters windows by app instead of scattering them.
The Dock — a list, not a preview
Here's the gap most people bump into: hovering a Dock icon shows you nothing. Right-click (or click-and-hold) a Dock icon and you get a text list of window titles — useful, but not a thumbnail. macOS has never shown live window previews on Dock hover the way Windows does, and macOS Tahoe (26) didn't add it either. That single missing feature is why a small category of apps exists.
And Cmd-Tab shows nothing at all
The built-in app switcher (Cmd-Tab) is icons only. Cmd-` cycles the front app's windows but shows no preview — you just watch windows flip by. Neither gives you a look before you land.
Third-party ways to get window previews
If you want Dock-hover previews or a thumbnail switcher, these fill the gaps. The honest landscape:
| Tool | What it previews | Trigger | Price | Open source |
|---|---|---|---|---|
| App Exposé (built in) | Current app's windows | Control-Down | Free | — |
| Mission Control (built in) | All windows, current Space | Control-Up | Free | — |
| Dock right-click (built in) | Window titles (text only) | Right-click Dock icon | Free | — |
| DockDoor | Live Dock-hover previews + Alt-Tab | Hover Dock / ⌥⇥ | Free | Yes |
| DockView / HyperDock | Live Dock-hover thumbnails | Hover Dock | Paid | No |
| AltTab | Thumbnail switcher | ⌥⇥ | Free | Yes |
| Let's Switch | Live preview in an MRU switcher | ⌥⇥ | Free tier / Pro one-time | No |
A few notes on the standouts:
- DockDoor is the go-to for the Dock-hover job specifically. It's free and open source, adds live previews on hover, and even puts close/minimize/maximize controls and swipe gestures on each preview. If "I want to hover the Dock and peek" is your whole ask, start here. (One caution its makers flag: there's a paid copycat on the Mac App Store — the only official source is dockdoor.net.)
- AltTab is the free, open-source thumbnail switcher — a genuinely great app, ranked at the top of several 2026 Mac roundups. Its overlay shows live thumbnails and you can type to filter. If you want maximum configurability at zero cost, it's the one to beat.
- DockView and HyperDock are the paid, closed-source Dock-hover options — polished, but doing a job DockDoor now does for free.
Preview while you switch: the keyboard-first way
App Exposé and Mission Control are great, but they're mouse-first and they don't remember what you were just doing — every window is treated equally, and you hunt through the whole pile.
Most switching, though, is a most-recently-used pattern: the window you want next is usually the one you were on a moment ago. That's the model behind Let's Switch. Hold Option-Tab and it flips through your windows newest-first — across apps and monitors, in one flat list — and the overlay shows a live preview of each window as you go. Release on the one you want. You get the preview and the switch in a single keystroke, no Dock detour, no mouse.
It also does the same-app job natively: hold Option-` to cycle just the front app's windows (the keyboard version of App Exposé, with previews and MRU order) — free, for as long as you like. When you want to jump by name instead of by order, Let's Switch Pro adds an Option-Space search palette that fuzzy-finds any open window and can launch any installed app. It's a quiet menu-bar app with no Dock icon of its own; pay-once, no account, no subscription, up to 20 devices per key, and no telemetry.
Two honest caveats: Let's Switch previews windows in the switcher, not on Dock hover — if you specifically want to peek without switching, DockDoor is the better fit. And like the built-in switchers, it works within your current Space rather than reaching across virtual desktops. It's also newer than the veterans, and it isn't open source.
Which one should you use?
- Just want to peek at an app's windows right now, no install? Learn Control-Down (App Exposé). It's already there.
- Want live previews when you hover the Dock? DockDoor — free, open source, purpose-built for exactly that.
- Want a keyboard switcher with thumbnails and every knob to tweak, for free? AltTab.
- Want the preview to happen as you switch, newest-first, with the least fiddling? Let's Switch — an MRU overlay with a live preview of each window, plus free same-app cycling.
For the fuller picture of the whole category, see our Mac window switcher guide and the Cmd-Tab alternatives roundup.
Frequently asked questions
Does macOS show window previews when you hover the Dock? No. Hovering a Dock icon does nothing, and right-clicking shows only a text list of window titles. For live thumbnails on hover you need a third-party app like DockDoor. The native preview features are App Exposé (Control-Down) and Mission Control (Control-Up).
What's the keyboard shortcut to preview a specific app's windows? Control-Down Arrow triggers App Exposé, which shows all open windows of the active app — including ones on other Spaces — as live previews. Add a same-app keyboard cycler with previews (Option-`) via Let's Switch if you want to flip through them one at a time.
Is there a free way to get window previews on Mac? Yes, several. App Exposé and Mission Control are built in. DockDoor and AltTab are free and open source. Let's Switch has a free tier that shows a live preview of each window as you Option-Tab through them.
Why doesn't Cmd-Tab show window previews? Cmd-Tab is an app switcher — it deliberately shows only app icons, one per app, not the windows inside. To see and switch by window with a preview, use a window switcher instead. See our how to switch windows on Mac with the keyboard guide for the full model.